Monday, 26 March 2012

A very mixed bag!

It was a really warm day yesterday, so I had to wait until the evening to let the kiln cool down enough to open it. Some nice pieces came out, but on the whole it was a rather disappointing firing. I thought I'd fixed the problem of my leaking sagger by sealing the top with kiln fibre, but air is still getting in somewhere. Several of my shino pots were completely oxidised, and this neph sye. shino glaze really doesn't like to breath, especially when it's laid on bubbles like crazy.

A few pieces were fully reduced, and they came out pretty well. This carved sake cup was probably the best of the lot:

It has a transparent ash glaze on the outside and the shino on the inside..the ash glaze has brought out the iron specks in the clay nicely.

Anyway, I'll say more about this firing later, but the sun is blazing outside and it's way too lovely to be sat by the computer!

Some time later..

Well, I just pulled the saggar out of the kiln, and I now know why most of the pots were oxidised. There's an enormous crack running the whole length of the container and about 3 mm wide! Oh's lasted just one firing, whereas the last one did around 15 before cracking. The rim was on a slight tilt, so I think the weight of the kiln shelf lid, plus pots on top of that, put too much strain on one side. I could make a new saggar from crank clay..but it's difficult to get the size exactly right, & good crank is very expensive..hey ho, back to the drawing board..

For the oxidised part of the firing (the part that was meant to be oxidised!), I experimented with an oribe glaze to which I'd added a little extra copper oxide to make it darker.

Sake cup, approx. 3 inches tall, cone 9

Sake cup, other side

Sake cup, underside & foot

I also tested a slip made with black iron oxide (rather than red), with hakeme brushwork over the top. The slip recipe was as follows:

50 kaolin
50 HVAR ball clay
6% black iron oxide
4% manganese dioxide
2% cobalt oxide

No blistering or bubbling of the slip layer this time, but the transparent glaze layer has thousands of tiny bubbles and pinholes in it, making it appear quite matt. I'm really not sure where the gases can be coming from as it isn't the white slip or the clay body..perhaps it's the manganese dioxide volatising or impurities in the iron oxide? It's possible that the glaze is applied a bit too thick, but more likely it needs extra flux to allow the gases to escape.

Bottle vase, approx 4 icnhes tall, cone 9

Two head cups came out okay. The one on the right (with shino glaze) should have been reduced but is mostly oxidised thanks to the cracked saggar. The one on the left is glazed inside and out with the matt ochre-ash was stood upside down on the tips of the horns, which worked really sticking to the shelf.

Head cups, approx 3 inches tall, cone 9.

The next piece was half reduced, half's the same shino glaze all over, but the top half was in the oxygenated part of the saggar. That's certainly a first for me!

Tea caddy, approx 6 inches tall, cone 9

Thursday, 22 March 2012

Earthenware lidded box

Made from stoneware clay and fired to around 1060 degrees C. Decorated with a pale yellow-orange slip and black slip in the impressions to give it a more aged look.

Approx 4 inches wide

Tuesday, 20 March 2012

Sculpture from play

I made this sculpture some time last year and have only just finished glaze-firing it. Another piece which resulted from simply playing around with clay, squeezing it into shape with both hands and seeing what might emerge. In this case, it took on quite a visceral form, so I added a bone-like structure to the outside, whilst keeping many of the marks and impressions made by my hands.

It was fired twice, first time with a black slip, then with an added brushed-on coat of manganese glaze to cone 5.

Sculpture, approx. 6 inches tall

Friday, 16 March 2012

Simple modes of expression

Inspired by African funerary jars of the Bura asinda people, I started making some small sculptures which could also be used as cups if you turn them upside down. I'm not sure why I enjoy making them but I think it has something to do with the uncertainty of the outcome. The decoration is unconscious to a great extent..I don't set out with an intention to create an expression or character for each piece, they just seem to emerge of their own volition. It's the same with the African vessels; the modes of expression are very simple and straightforward but the elements come together to express something more, something which is difficult to define but which is innately human and alive.

Head cup, approx 2 inches tall

Head cup (other side)

Head-cup, approx 2.5 inches tall

It's taking me a while to get around to glazing these..I still have another five or six of them lying unglazed in the studio. I haven't put glaze on the inside as they need to stand this way up in the kiln. I was thinking I might dip some of them fully in shino and then fire them on their heads on shells..the shell marks might add interest to the design. Also, I've made a couple with three horns, which will act as feet for the cup and allow me to stand it upside down and almost fully glazed in the kiln.

The one in the last photo above was glazed with a simple Nami-jiro glaze which consists of 50/50 ball clay and wood ash with a little kaolin added. I'll probably re-glaze this piece as I'm not overly keen on the lighter coloured drips that formed. I'll maybe brush over it with my matt ochre-ash glaze.

Thursday, 15 March 2012

A minor dilemma

Sometimes in ceramics we're faced with little dilemmas.."should I fire this lid in place and risk the glaze running off, or should I fire it separately, and risk it warping?" Yesterday, I was only firing to cone five, so I decided to place the lid of this carved box on the kiln shelf, as I didn't think the temperature would be high enough to warp it.

(btw, I've hidden the warp on this photo)

Wrong decision! Turns out the temperature wasn't high enough to make the glaze run, but the lid warped very slightly, so it no longer fits perfectly. Not by very much, but enough to be annoyingly noticeable. Hindsight is a wonderful thing, and now I'm kicking myself, realising that in this case, leaving the lid in place was most likely the sensible option.

Having said that, it's possible that it would have warped anyway, who knows. I'll try firing it again with the lid on and see if it settles down.

Here is another piece from the same firing:

Carved vase, approx 6 inches tall

This high manganese glaze was fired to cone 5 and has come out nicely with an even black colour and fairly shiny surface. Ideally, I would like to fire this glaze a little higher, between cone 5 and 6, but it's very difficult to judge accurately without a pyrometer.

Never give up..the best is yet to come!

Wednesday, 14 March 2012

Native American pottery

The other day, I stumbled across this little gem of a pot in a second-hand shop. It was made by the Navajo People - The Diné. It's about 3.5 inches tall and sits in the hands beautifully. I'm guessing the pot was coiled, given the irregular shape of the mouth, though I suppose it could have been cast from a coiled original. If it was coiled, the maker is extremely skilled as it's wafer thin and the inside is perfectly smooth. The outside has been painted, perhaps with terra sigillata, then etched to reveal the lovely warm orange of the clay body.

I was drawn to this piece because I brought back a Navajo bottle vase from the USA when I was on holiday there in 1999. Maybe it says something about modern society that I paid less for this hand-crafted pot than an hour's parking in the town centre.

It's a shame I can't make out all of the signature. If anyone out there knows anything about the artist, I'd be really interested to learn more about her/him.

Sunday, 11 March 2012

Throwing off the hump

I thought I'd have a first go at filming myself throwing today. Must say, I did feel quite conscious of the camera, and it was more difficult to concentrate and lose myself in the process. I chose the first clip as I had a couple of problems with an air bubble in the clay and the bottom starting to sag, which maybe makes it a little more interesting to watch. Apologies for the noisy wheel (bearings are going) and my noisy's one of of those weeble-wobble Ikea stools with a base wider than the seat. I'm always tripping over the thing!

Saturday, 10 March 2012

Making lidded jars

Last week I made several of these lidded jars or urns. I was inspired by images of ancient megaliths and I wanted to create some vessels which communicate a similar kind of heft and gravitas. I don't know how far I've's difficult to achieve that with small pieces, so at some point, I'd like to make these on a much larger scale. Making the lids is challenging to say the least, and I'm still trying to work out the best way of doing that from a closed form.

Lidded jars drying, approx. 6 inches tall.

At the moment, I'm adding the inner lid flange by hand, as a coil, then pinching it out, letting it dry a little, and then trimming and scraping it down to fit. It's quite a fiddly and time-consuming process.

I'm already thinking about how I should glaze these jars..I will probably fire them with the lids in place, so I need to use a glaze which definitely won't run. Traditional shino is one possiblility or perhaps some black slip decoration covered with the matt ochre-ash, which I might try pouring over one or two of them. The two pieces below have this matt ochre-ash glaze:

Beer cup, six inches tall

Bowl, approx 3.5 inches tall

Tuesday, 6 March 2012

Feels like spring at last!

Today feels like the first proper day of spring. Started off quite misty this morning but this afternoon the sun was really bright and warm, and I even put some pieces outside to dry. Daffodils are blooming and trees are starting to bud, including my Japanese larch bonsai, which has pine cones on it for the fist time in sixteen years.

And then I just took this shot for the colours:

Now I really must get back to throwing those pots I was supposed to make this morning!

Friday, 2 March 2012

Pots can definitely grow on you

I made this little pot some time ago now, and I've glaze-fired it three times..once in reduction and twice in oxidation. Each time I wasn't really satisfied with the finish and brushed on another layer of glaze, and even when I took it out of the kiln last time, it didn't strike me as being particularly attractive. It's been knocking around in my workshop for several months, and I kept picking it up, turning it round, putting it down, wondering whether I should bother to put it in for a fourth firing.

Carved pot with ochre-ash glaze, 3.5 inches tall

Then the other day I took it outside and looked at it more closely. In the bright daylight I could better appreciate the subtle sheen of the ochre-ash glaze which contrasts with the harsher mottled areas of burned-out iron. I began to like the way this glaze shows every detail of the clay surface, every single mark left in the making process, and the way it pools in the crevices into darker shades of grey-green.

Pots can slowly grow on you...or maybe as with people, it becomes easier to accept their imperfections once we have lived with them for a while..